Drugs

Question 1

Penicillins

What infections are they used in and what are the side effects

Answer 1

Benzylpenicillin: Bacterial menegitis

Amoxicillin (broader spectrum): Respiratory infection, Otits Media, UTI’s

Flucloxacillin (modern methicillin - β-lactamase resistant): Cellulitis

Piperacillin (extended spectrum): Severe infections, Pseudomonons

Hypersensivity (skin rash / fever)
-Anaphylaxis
-Antibiotic-associated Diarrhoea
Contraindications: Penicillin allergy

Question 2

Cephalosporins

Answer 2

2nd Gen: Cefuroxime

3rd Gen: Cefotaxime Ceftriaoxne

1st generation: main activity against gram +ve bacteria

2nd generation: less active against gram +ve, more active against gram –ve:

-Meningitis [cefotaxime] -Bronchiectasis [ceftazidime]

Diarrhoea

• Nephrotoxicity
• Occasional alcohol intolerance
• Headache

Question 3

Monobactams

Answer 3

Aztreonam: Pseudomonas -Other gram -ve aerobic rod infections

GI Upset

Beta lactam antibiotic
Only effective against gram (-)

Question 4

Carbapenems

Answer 4

Meropenem

Imipenem

Both used in septic shock
Very broad spectrum against gram + and -

GI Upset

Question 5

Glycopeptides

Answer 5

Vancomycin: Severe C. Difficile -MRSA -Bacterial endocarditis

non- β-lactam inhibitor of bacterial cell wall syntheses. non- β-lactam inhibitor of bacterial cell wall syntheses

Ototoxicity

• Nephrotoxicity
• Rash

Question 6

Macrolides

Answer 6

Clarithromycin

Erythromycin

Both: Same antibacterial spectrum as penicillin, therefore useful alternatives where patient is allergic.
-Ayptical Pneumonia -Other bactieral infections with penicillins

-GI Upset
-Hypersensitivity reactions
- Antibiotic associated
diarrhoea
- Interacts with other drugs due
to their effects on cytochrome
P450 in liver: inhibits
metabolism of ciclosporin and
theophylline

Question 7

Aminoglycosides

Answer 7

Gentamicin

Tobramycin

Effective against aerobic gram –ve and some gm +ve
Used (esp. synergistically) in:
-Sepsis/ septicaemia
-Meningitis
-Endocarditis
-Pseudomonas (Tobramycin anti-pseudomonal antibiotic)
Reduce dose and frequency in renally impaired.
Monitoring: -Endocarditis - 8 hourly -Measure serum levels after 1st dose.

Vestibular & auditory damage (ototoxicity-deafness/vertigo) - usually progressive and irreversible damage to the sensory cells in the vestibulocochlear apparatus.
-Nephrotoxicity (damage to kidneys tubules, usually reversible when drug stopped) *Nephrotoxicity leads to reduced clearance, leading to a vicious cycle, leading to further nephrotoxicity and eventually renal failure.

Question 8

Tetracyclines

Answer 8

Doxycycline

Tetracycline

Treatment of -Chlamydia -Syphilis -Resp infections (Community acquired pneumonia) -Cellulitis -Acne -Chronic bronchitis Doxycyline can also be used for malaria treatment and prophylaxis

• Nausea, vomiting, diarrhoea
• Dysphagia and oesophageal irritation
• Teeth discolouration
• Rashes
• Chelate calcium-never give to pregnant/children

Question 9

Quinolones

Answer 9

Ciprofloxacin

Levofloxacin

Moxifloxacin

Particularly active against gram –ve bacteria:
-Haemophilus Influenza -Pseudomonas -Gram -ve enteric coliforms
Used against: -UTIs -Resp infxs in CF patients - Pnemonia (Levofloxacin) -Salmonella -Gonorrhoea

GI upsets: nausea, vomiting, diarrhoea, abdominal pain.
Interactions: Inhibits the cytochrome P450, increasing theophylline toxicity.
-C Diff risk
-Hypersensitivity
-Headache, dizziness, convulsions (Caution in epilepsy)